“Scientists warn that large-scale fracking for shale gas planned by Mexico’s oil company Pemex will cause a surge in seismic activity in northern Mexico, an area already prone to quakes.
Experts link a 2013 swarm of earthquakes in the northern states of Tamaulipas and Nuevo León to hydraulic fracturing or fracking in the Burgos and Eagle Ford shale deposits – the latter of which is shared with the U.S. state of Texas.
Researcher Ruperto de la Garza found a link between seismic activity and fracking, a technique that involves pumping water, chemicals and sand at high pressure into the well, opening and extending fractures in the shale rock to release the natural gas.
“The final result is the dislocation of the geological structure which, when it is pulverised, allows the trapped gas to escape,” the expert with the environmental and risk consultancy Gestoría Ambiental y de Riesgos told IPS from Saltillo, the capital of the northern state of Coahuila.
When the chemicals are injected “and the lutite particles [sedimentary rock] break down, the earth shifts,” he said. “It’s not surprising that the earth has been settling.”
De la Garza drew up an exhaustive map of the seismic movements in 2013 and the gas-producing areas.
His findings, published on Mar. 22, indicated a correlation between the seismic activity and fracking.
Statistics from Mexico’s National Seismological Service show an increase in intensity and frequency of seismic activity in Nuevo León, where at least 31 quakes between 3.1 and 4.3 on the Richter scale were registered.
Most of the quakes occurred in 2013. Of the ones registered this year, the highest intensity took place on Mar. 2-3, according to official records.”
Read more: IPS